"As a country, we're essentially tossing every other piece of food that crosses our path. That's money and precious resources down the drain," said Dana Gunders, a scientist with the Natural Resources Defense Council's food and agriculture program.

The NRDC report said Americans discard 40 percent of the food supply every year, and the average American family of four ends up throwing away an equivalent of up to $2,275 annually in food.

Just a 15 percent reduction in losses in the U.S. food supply would save enough to feed 25 million Americans annually. It also would lighten the burden on landfills, where food waste makes up the largest component of solid waste, according to the NRDC, a nonprofit environmental organization.

Particularly worrisome, the organization said, was evidence that there has been a 50 percent jump in U.S. food waste since the 1970s. Unsold fruits and vegetables in grocery stores account for a big part of the wasted food.

But consumers and restaurants are also to blame, preparing large portions that result in leftovers that often go uneaten.

The NRDC said it is asking for the U.S. government to study losses in the food system and set goals for waste reduction.

"No matter how sustainably our food is farmed, if it's not being eaten, it is not a good use of resources," said Gunders.